Bottle-necked system?

[Roaring Panda]

Hey, I built my system back in last July, which had some PSU problems causing crashing on the more powerful games. Recently, I managed to scrape together enough money to replace the PSU with plenty to spare. The problems have stopped now, but I'm worried that my system isn't performing as well as it should be! On Crysis< 1920x1200 full settings, no anti-aliasing I get about 20-30fps average, on STALKER Call of Pripyat, same settings + resolution I get a similar framerate and on world in conflict I average about 30-35 fps. Is this not right for my system? How can i fix it? If it is correct, how should i go about upgrading It next?

Mobo: Asus P5QL
Graphics Card: Geforce GTX 280 1gb
Processor: Intel Q6700 Quad Core CPU
RAM: 4gb Corsair TWIN2X4096-8500C7 DDR2
Cooling: 3x 120mm Fans.
PSU: Corsair HX 750w
HDD: Hitachi

 

[Roaring Panda]

Oops, forgot to add HDD. Its a Hitachi Hds721010cla332 3.5inch 1tb 32mb Sata 7200rpm

 

[batuchka]

I would hit an aftermarket cooler and clock that chip a wee bit? Looks decent still for games with an OC...

 

[Roaring Panda]

I've already got an aftermarket cooler, but I haven't clocked the chip just yet. Are there any decent guides about for overclocking CPUs? I'm pretty bad with overclocking, never gone near it!